The FDA has sent warning letters to four pharmaceutical companies citing them for omitting and minimizing information about risks and exaggerating potential benefits in material promoting their drugs.

The letters order the companies to cease banned marketing behaviors and instruct their employees on rules for promotions, but do not impose any fines or other sanctions.

Among the companies reprimanded are Amylin Pharmaceuticals and Eli Lilly & Co. for their diabetes drug Byetta. The FDA letter notes that at a meeting of the Endocrine Society in June, an Amylin representative told an FDA employee that the drug caused 80 percent of patients to lose seven to eight pounds in 30 weeks of treatment. When the FDA representative asked about the source of that claim, he was provided with copies of two published studies that did not support it.

The letter states that Amylin representatives made other misleading or false statements about the drug’s benefits, and suggested that it could be used as a standalone treatment. At the time of the conference, Byetta was not yet approved as a standalone drug, making it illegal for the company to promote it for that use.

Eli Lilly was also taken to task for “entirely [omitting] risk information” in a print ad for the antidepressant Cymbalta, and for minimizing risks and exaggerating benefits in another ad.

Finally, the FDA sent a letter to Bayer over its marketing campaign for the intra-uterine device Mirena. In addition to playing down risks and making false and misleading statements, the FDA notes that Bayer’s ad campaign makes unsubstantiated statements claiming that “the use of Mirena instead of other means of contraception will result in increased levels of intimacy, romance, and by implication, emotional satisfaction.” The ads also promise that women who use the device will “look and feel great.”

The FDA is unaware of “any evidence suggesting that women who are using Mirena for birth control look great or feel great,” the letter reads.